Asphalt emulsions have been employed for numerous and wide variety of applications for many years. As is known in the art, these emulsions may be cationic, anionic or non-ionic depending on the type of emulsifier used, and they may be either rapid set, medium set or slow set. Representative of the cationic emulsifiers are the fatty amines, lignin amines, quaternary ammonium halides, including diquaternary compounds, and alkyl-substituted imidazolines. The alkylphenoxypolyalkyleneoxyalkanols, e.g., the reaction product of nonylphenol with ethylene oxide, represent a common non-ionic emulsifier while alkali metal salts of fatty acids and of petroleum sulfonates are representative anionic emulsifiers. One of the problems encountered with asphalt in such emulsions is that its adhesion to various substrates and especially to aggregate needs to be improved. Such aggregate is represented, for example, by gravel, crushed rock, slag, sand and crushed limestone. Additionally, the adhesion of asphalt needs to be improved with respect to other material such as, for example, cementitious materials, metals, glass and the like.
An improved asphaltic emulsion is provided in accordance with this invention, in which the asphaltic composition in the emulsion is the product produced by reacting an acrylamide with asphalt having a viscosity of less than about 120,000 cps, and most desirably less than about 60,000 cps (at 140.degree. F.), a vinyl aromatic monomer and a rubbery polymer.
Some of the desirable properties of the present emulsions and the asphaltic material therein include improved coatability of negatively charged surfaces, improved adhesion, less stripping, improved flexibility, particularly at low temperatures, improved strength, reduced high temperature flow, increased durability, better compatibility with polymers.
While such asphalt emulsions are of great value for many applications, an emulsion of an asphaltic material having the desirable properties noted above would be of even greater value provided the material can be easily emulsified using conventional emulsion manufacturing equipment and emulsifiers. The present invention provides such a material and such an emulsion.